6. Mustard
Whether it’s wholegrain or Dijon, the preservatives used in mustard are meant to keep it bacteria-free even when it’s stored in the fridge. In fact, some containers indicate that refrigeration isn’t necessary after opening.
However, mustard loses both its color and flavor fairly quickly. In other words, you’ll significantly improve its quality if you store an open jar of mustard in the fridge.
7. Mayonnaise
Sorry to disappoint, but that opened jar of mayonnaise shouldn’t be stored in the pantry. Mayo contains raw eggs, which can carry salmonella, a dangerous bacteria that can lead to severe gastrointestinal issues. While refrigeration doesn’t kill salmonella, it does slow the growth of the bacteria, which is why it’s recommended to refrigerate mayonnaise.
You may buy mayonnaise from a non-refrigerated shelf, but once you open it, you must store it in the fridge. In fact, according to the USDA, opened mayo should be thrown away in the bin if its temperature reaches 50°F or higher for more than eight hours.
